Mill for reducing



2 Sheets-Sheet; 1,

L. SMITH. Mill'for Reduoing,Levigating, 8:0.

No. 223,769. Patented Jan. 20,1880.

,2 Sheets-Sheet: 2'. L. SMITH. f

Mill for Reducing, Levigating, &c.

N0."223,769. Patented Jan. 20,1880

- I f f N. FETDES. PKOTID-LITISOGRAPHIER, WASHINGTON. D O.

UNITED STATES PATENT OFFICE.

LEANDER SMITH, or oInoINNA I, oHIo;

MILL FORREDUCING, LEVlGATING, etc.

SPECIFICATION forming part of Letters Patent No. 223,769, dated January 20, 1880.

Application filed December 5, 1879.

To all whom it may concern I Be it known that I, LEANDER SMITH, of Cincinnati, inthe county of Hamilton and State of Ohio, have invented certain new and useful improvements in mills for grinding, comminuting, or levigating grain, ores, paints, brewers and distillers mash, and other vegetable, mineral, or animal substances, of which the following is a specification.

The invention relates to that class of grindin g or pul verizin g mills in which a roll or rolls is caused to turn within an inclosing-drum, and the material is comminuted between the internal periphery of the drum and the face of the roll or rolls; and it consists in placing theroll diagonally through the drum in giving to it such a longitudinal contour that it may rest evenly in contact with the sides of thedrum throughout its length when so placed;

and in the combinations and details of construction hereinafter described and claimed.

In the drawings, Figure 1 is a front elevation of the machine, with a drum-head and spout shown in broken lines. Fig.2 is an end view, the drum-head being removed; Fig. 3,

'a vertical section upon the line ac x of Fig.

2, showing a roll in position; Fig. 4,21- roll detached.

Upon a suitable framework, A, is mounted the drum or casing B. This drum may be of any appropriate material, and is preferably fixed upon the frame so as to be held against revolution. It may be made in halves hinged or bolted together, so that the upper portion may be openedor lifted off to allow access to the interior. Lengthwise through the axis of the drum runs a shaft, 0, turning in bearings c c in'the frame-work, and having near each end or head of the drum radial arms a a, slot ted at their extremities for the reception of the journals or trunnions b b of the roll D. The number of these arms may vary from one at each end of the drum, to hold a single roll,

up to four or even more, tohold a series of rolls. Ordinarily, however, not less than two rolls will be used. The slots may be open slots, extending entirely to the end of each arm, or they may be closed at the end by an adjustable block, whereby the roll may be permitted to come in contact with the casing, when in action, to finely comminute the'material, or may be stopped short of its periphery, in order to simply granulate.

The roll-is to be so placed that it will lie diagonally in the drum, as shown in Fig. 3, thus conducin g to the regular and equable forward feed of the material under treatment. That itmay be properly held and retained in this position, the radial arm in which it bears at one end of the drum should be in advanceot the one at the other end. In order that it may be in contact with the drum throughout its whole length, it musthave the longitudinal contour which would be indicated by the line of section made with the drum by a plane let fall from the axis of the roll perpendicularly to the side or working-face of the drum. The drum is preferably made with straight sides, either having a uniform diameter from end to end or the form of a truncated cone. It may, however, be moderately bell shaped, or be slightly larger in the middle than at the ends. The shape of the roll will be somewhat modified according to these constructions. As a rule, it will be an elongated oval.

In dry-grinding the ends of thedrum should be closed by a cap or diaphragm, the material to be oomminuted being introduced through the hopper E in one head and discharged at the other end by means of a suitable opening or spout. In wet-grinding or levigat-ion the discharge end may be open, or only sufficiently closed by a shield to prevent spatterin g.

. The shaft is turned in such direction that the material to be ground, as it enters the drum, falls beneath the retreating end of the rolls, and is gradually fed down toward the discharge-spout by the action consequent upon their rotation on diagonal axes, while at the same time it is thoroughly oomminuted between the side of the drum and the face of the rolls. The centrifugal force generated by the rapid revolution of the shaft carries the rolls out and causes them to press toward and against the walls of the drum, the slots in their supporting-arms permitting them to accommodate themselves to the progressively-reduced state of the material.

ward the opposite end of the cylinder as it falls from the receiving-spout.

The drum, instead of being stationary, may be caused to revolve in the direction in which the roll travels, but at a different rate ofspeed, or in a contrary direction at any suitable rate; or one or more rolls may be retained in a diagonal position in the drum while the latter is revolved; and the pressure of the rolls may be regulated by springs, or weights, or rope and pulleys. A positive lengthwise reciprocation may be given to the drum, or to the rolls as they revolve, by means of a cam upon the shaft or gudgeon of either, in the manner well known in crushing or roller mills; or the rolls may be mounted, as shown, with sufficient latitude between their shoulders and the armsin which they bear to permit a limited endwise play; but neither of these constructions is absolutely essential to good work.

Instead of a single set of long rolls, reaching from end to end of the cylinder, two or more sets of short rolls may be used, and the arms for these sets may be so arranged that the ends of the rolls in one set may slightly overlap those in the next, or so that there will be a distinct line of division between each set. The rolls of one set or gang may be of less diameier than those of the preceding, so as to have a greater peripheral speed, and the difference in size will permit the number to be increased. A single cylinder may therefore be combined with a series of gangs successively decreasing in size and increasin g in number of rolls from the head to the tail of the cylinder. The rolls of alternate gangs may also be arranged longitudinally, or the axes of the rolls in one gang may lie at a different angle to the axis of the cylinder from those of the succeeding gang.

The thoroughness with which the material is reduced or levigated will be determined by the speed and pressure of the rolls and the length of time it is under their action. The speed can readily be controlled through the gearing. The pressure will depend upon the speed or weight, and the time upon the trend of the rolls and the shape, length, and inclination of the drum. In some cases, therefore, it will be well to make the inclination adjustable by means of screws, cams, or other common adjusting devices.

The rolls are readily removable from their hearings in order that others may be substituted, or that they-may be occasionally changed end for end to prevent the perpetuation of defects or formation of ruts.

I claim as my invention- 1. The combination of a drum or casing, having at one end a hopper or induction-tube and at the other a suitable opening or discharge-spout, with a comminuting-roll placed diagonally to the length of said drum, and having a longitudinal contour to bring it evenly in contact with the sides thereof, substantially'as described.

2. The combination of the drum or casing, the shaft, the arms upon said shaft, and the roll or rolls retained by said arms in a position diagonal to the length of the casing, substantially as described. 1

3. The combination of the drum or casing, the shaft, the arms upon said shaft, and one or more gangs of rolls mounted in said arms, so that the rolls of a gang have a position diagonal to the length of the casing, substantially as described.

LEANDER SMITH.

Witnesses:

R0131. H. PARKINSON, DANL. KELLY. 

